User manual

Protocol Analysis
R&S
®
RTO
269User Manual 1316.0827.02 ─ 06
7,0x01,Temperature
7,0x12,Pressure
10,0x123,Speed
# ID as integer
7,17,Brake
# ----------------------------------------------------------------------------
SCPI command
● BUS<m>:I2C:FRAMe<n>:TRANslation on page 662
10.3 SPI Bus
10.3.1 The SPI Protocol
A 4-channel instrument is required for full support of the SPI protocol.
The Serial Peripheral Interface SPI is used for communication with slow peripheral devi-
ces, in particular, for transmission of data streams.
Main characteristics of SPI are:
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Master-slave communication
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No device addressing; The slave is accessed by a chip select, or slave select line.
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No acknowledgement mechanism to confirm receipt of data
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Duplex capability
Most SPI buses have four lines, two data and two control lines:
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Clock line to all slaves (SCLK)
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Slave Select or Chip Select line (SS or CS)
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Master data output, slave data input (MOSI or SDI)
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Master data input, slave data output (MISO or SDO)
When the master generates a clock and selects a slave device, data may be transferred
in either or both directions simultaneously.
Fig. 10-5: Simple configuration of SPI bus
The data bits of a message are grouped by following criteria:
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A word contains a number of successive bits. The word length is defined in the pro-
tocol configuration.
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A frame contains a number of successive words, at least one word.
SPI Bus